Louisiana Tigers was the common nickname for certain infantry troops from the State of Louisiana in the Confederate army during the American Civil War. Originally applied to a specific company, the nickname expanded to a battalion, then to a brigade, and eventually to all Louisiana troops within the Army of Northern Virginia. Although the exact composition of the Louisiana Tigers changed as the war progressed, they developed a reputation as fearless, hard-fighting shock troops.
Thus, we now have the LSU Tigers. Other states adopted their own:
Tennessee is known as the "Volunteer State", a nickname some claimed was earned during the War of 1812 because of the prominent role played by volunteer soldiers from Tennessee, especially during the Battle of New Orleans.
So I just kept the pattern going.